The present invention relates generally to a baffle in a clarifier tank for gravitationally separating solids suspended in a liquid contained in the tank. These baffle devices are also known in the art as a lamella gravity separator or settler. The clarifiers with which the inventive baffle device is used typically consist of a circular or rectangularly-configured tank in which a centrally mounted, radially-extended arm is slowly moved or rotated about the tank at or proximate the surface of the carrier liquid. For a more detailed description of the individual non-vented baffle and non-vented baffle system, U.S. Pat. No. 5,252,205 to Schaller is referred to and hereby incorporated by reference.
The present invention provides a vented baffle that is mounted in cantilevered fashion along a peripheral wall of the clarifier intermediate the tank bottom and the surface of the carrier liquid contained in the tank. The vented baffle system includes a plurality of such baffles which are constructed as modular units and form a continuous, single-surface sheet that slopes downwardly from the peripheral tank wall toward the center of the tank and terminates at a free edge suspended in spaced relation above the tank bottom. More specifically, each panel member which is downwardly sloping from the peripheral tank wall toward the interior of the tank and the tank bottom, is provided with a lower side and an upper side. The panel member extends downwardly from an upper edge secured to the peripheral tank wall to a lower edge disposed in spaced relation to the tank bottom. The panel member has a first lateral side and a second lateral side with the panel member defining a space formed between the junction of the lower side of the panel member and the peripheral tank wall. Due to the inclined configuration of these baffles, air may be trapped during the filling of the tank in a space formed between the junction of the lower side of the panel member and the peripheral tank wall. As well other gases which may form naturally as a part of the chemical processes which take place within the clarifier may be trapped in this space. Accordingly, the forces imposed by these gases on the baffle require that the baffle be constructed and mounted in such a manner that will withstand these forces. As well, the build up of pressure from these gases can be extreme with damage and/or personal injury resulting unless some form of venting is provided.
A common form of venting relies on one or more holes drilled in the baffle panel member to continually vent the gas to the surface and alleviate the build up of pressure. Small holes (1 inch diameter or less) however rapidly become clogged with sludge and become ineffective. Larger holes allow the continual upflow of waste solids and can create a negative impact on the performance of the baffle.
Numerous clarifier and baffle configurations are disclosed in the art. However, prior art attempts have suffered from a variety of various drawbacks and deficiencies.
For example, in U.S. Pat. No. 4,109,433 to Maze relates to a ventilator for spaces under slanted roofs or attics such as a gable, hip and shed roof types. Specifically, the ventilator uses an elongate duct positioned between the adjacent rafters under a roof. However, there is no disclosure in the reference of an improved vented baffle system which is constructed as a modular unit and that consists of a plurality of interengaged individual baffles, each formed as a unitarily-integrated element incorporating the panel member, a vent means and an integral end bracket for suspended securement of the baffle to the peripheral wall of the clarifier tank.
U.S. Pat. No. 5,286,392 to Shea is directed to a launder and baffle structure used in association with a filtration tank of which the type using granular filtration media is disclosed. Specifically, a regulable air discharge system is disclosed to release a selected amount of air from beneath the baffle system in order to regulate turbulence and thereby facilitate quiescence of flow. This reference, however, does not teach an improved vented baffle system having a plurality of baffles with each baffle consisting of unitarily-integrated design incorporating a panel member, an end bracket for cantilevered securement of the baffle to the peripheral wall and a relief valve means which is in fluid communication with the space formed between the junction of the lower side of the panel member and the peripheral tank wall preventing the pressure in said space.
It is, therefore, an object of the present invention to provide a system of plural integrated vented baffles, curved to match the peripheral contour of a circular or arcuate tank or, alternatively, linear to match the peripheral walls of a non-circular tank, and which interlock to form a rigid "shelf" or baffle system inclined inward and downward around the entire periphery of the tank.
Another object of the invention is to provide a relief valve means in fluid communication with the space formed between the junction of the lower side of the panel member and the peripheral tank wall preventing the pressure in the space.
A further object of the invention is to provide a relief valve means which opens and closes dependent on the pressure exerted by the gas pressure in the space.
Another object of the invention is to provide a relief valve means which is located between the substantially vertical peripheral wall and the panel member so that venting of gases may be accomplished.
Another object of the invention is to provide a relief conduit passage in fluid communication with the space formed between the junction of the lower side of the panel member and the peripheral tank wall preventing the pressure in the space and which is integrally molded into the mounting flange.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.